All eyes have been on Tesla's planned massive battery factory, under construction just outside of Reno. But on the other side of the country, in Cambridge, Mass., you'll find an undercover startup that's been toiling away at a totally different way to design and make what company executives say is a better battery for the power grid and electric cars.

The company, 24M, which came out of stealth mode on Monday, is working on a new type of lithium ion battery that it says is vastly cheaper than what's currently on the market. The company describes their innovation as "the most significant advancement in lithium-ion technology in more than two decades," and if the battery can deliver on its promise it could help deliver low cost batteries for important new emerging markets.

Over the years there have been dozens of young startups that have tried to disrupt the battery industry with new ideas. But few actually pull it off. 24M will face intense competition in a crowded market that favors large companies like the battery giants Panasonic and LG in Asia.